Radio signaling



Jan. 26, 1932.

M. A. GIBLIN RADIO SIGNALING Filed Feb. 26; 1926 2 Sheet-Sheet 1 M a@MEN'TOR.

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RADIO SIGNALING Filed Feb; 26. 1925 2 Sheets-Sheet 2 Fig.6.

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.1 TTORNEYS Patented Jan. 26, 1932 PATENT OFFICE v MARC A. GIBIIIN, OFWEST ALLIS, WISCONSIN, ASSIGNOR OF ONE-HALF TO HARRY W.

BOLENS, OF PORT WASHINGTON, WISCONSIN RADIO SIGNALING Application filedFebruary 26, 1926. Serial No. 90,787.

This invention relates to improvements in the art of radio signaling andmore particularly to broadcast receivers, radio frequency transformerstherefor, and methods and forms for the construction of suchtransformers.

While the transformer herein to be described is capable of generalapplication to any standard circuit, it is perculiarly adapted touni-control receivers in which the transformers used in couplingsuccessive stages of amplification must be accurately balanced with eachother both as to their initial capacity and as to their ratio ofcapacity to inductance as affecting their respective increments ofchange during tuning.

It is the primary object of this invention to provide a transformereconomically and by methods so 'susceptible of standardization as toensure the accurate reproduction of any required number of transformerinstruments of like characteristics and capable of receiving a slightdegree of initial adjustment which will harmonize their respectiveinductance values without appreciable changes in their predeterminedcapacities. In achieving this result the design of the transformeritself is important and the manner of its construction and the form usedin its manufacture are of primary importance.

* In the drawings:

Figure 1 is an isometric view of a form for th manufacture of coils inaccordance with this invention.

in order more clearly to show the construction.

Figure 6 is a plan view of the top of the first unit of the transformersection embodying a slight modification.

Figure 7 shows in side elevation a fragment of the unit appearing inFigure 6.

Figure 8 is a conventional circuit diagram illustrating the manner inwhich this invention is used in making commercial radio receivers andillustrating conventionally the relative positions and connections ofthe PI'i1 mary and secondary windings of the several transformers andthe manner inwhich the secondaries of the number of transformers made inaccordance with this invention may be tuned to resonance to a commonfrequency by means of a set of condensers having movable platesinterconnected as by mounting on a single shaft.

Like parts are identified by the same reference characters throughoutthe several views.

The form upon which the coils are wound is shown in Figures 1 and 2. Itincludes a tubular core 10 which is provided with slots 11 opening toone end thereof and extending in substantial parallelism on oppositesides of the axis to divide the body of the core into two parts 12 and13. Below the lower ends of the slots, these two parts of the core areconnected integrally by an unslotted annular portion.

Upon core 10 are mounted a plurality, preferably at least four, ofsegmental form sections circumferentially spaced from each other to bereadily collapsible when the core is drawn from between them. It will benoted that segmental winding form sections 14: and 15 are mounted onpart 12 of the body and sections 16 and 17 are carried by part 13. Inorder to fix the positions of the several segments accurately on thecore While providing for the ready withdrawal of the core the uppermargins of the core parts 12 and 13 are notched to receive the keys orpositioning pins 18 carried centrally by the several segments in acentripetally projecting direction. (Io-operating with these pins arethe screws 9, one for each segment, threaded to the core.

The space between segments 15 and 17 and that between segments 14 and 16are aligned pose of reducing distributed capacity in the coils. Inaddition to grooves 19, it is convenient to provide axially extendinggrooves at 20 for the purpose of receiving stays which may enter intothe construction of the coils. Grooves 20 are spaced equally about thecircumference of the coil on either side of slots 11 which may performthe same function.

It is very important to note that the winding form above described, andparticularly the core ortion thereof, should be absolutely rigid.therwise the tension of the wire wound thereon will gradually contractthe ,form by drawing parts 12 and 13 toward the center. This will changethe characteristics of the coil and the desired uniformity of successivecoils will be impossible. It is preferred to use solid metal for theform.

The form described is adapted to permit the winding of D-coils or figure8 coils. The completed unit is in effect two air core windings ofopposite polarity and constructed from a conductor or conductors to formalternately a turn in each.

In practice, the method of winding the coils is as follows:

The secondary 24 is wound first. With its end 25 held in the bottom ofone of the slots 11, a conductor is wound about the two segments on corepart 12 as at 26 (see Figure 3) and thence diametrically across the formthrough the two slots 11, as at 27, to the margin of segment 16. Fromthere the wire passes around the two segments 16 and 17 as at 28 and iscarried back through the two slots 11 on a slightly different diameter29 of the form to a winding groove in segment 14 immediately about thepoint of beginning. This operation is repeated at the levels defined bythis and successive grooves until the major portion of the secondarywinding is in place. When the secondary winding reaches the point atwhich the primary is to begin, the two windings can be placedsimultaneously in alternate-grooves. This results in very closeinductive coupling with little capacity coupling proportionately.

The primary 30 is preferably so disposed with reference to the secondarythat when the end of the primary winding is reached a few turns of thesecondary will remain to be wound. These turns are separately mountedfor reasons to be specified hereafter.

At this stage of the winding operation, a skeleton sup ort 32 of somekind is associated with t e turns already wound and is fastened theretowith a suitable adhesive. This support may comprise a tube of such asize as to fit closely over the winding and having portions of its sidewalls cut away to leave integrall the end annuli 33 and spacing bars 34.The support may also be constructed as shown in Fi ures 6 and 8 ofseparate annuli and spacing ars suitably fastened together as byadhesion.

It is particularly to be noted that in each of the two constructionsillustrated for sup port 32, the arrangement is such as to spacepositively the corners of the two D-coils which comprise eachtransformer unit. As has already been indicated, the spacing between thecorners of the D-coils is determinative of selection, and for thepurposes of this invention accuracy in spacing is most important. In theFigure 5 construction the arcuate extent of the spacing bars 34 issufiicient to bridge the gap between the corners of the D-coils andtooverlap adjacent peripheral portions of the D-coils to such an extentthat such peripheral portions can be cemented thereto. In theconstruction shown in Figures 6 and 7 the spacing bars have considerablyless peripheral extent and are so designed as to fit between the cornersof the D-coils, as is clearly shown in Figure 6. A convenient method ofconstruction involves the use of celluloid strips at 34 in the deviceshown in Figure 6. These strips when treat- 190 ed with acetone orbanana oil soften and become highly adhesive. As the banana oilevaporates the strips solidify in adhesion to the adjacent corners ofthe coils, and their location between such corners is such as to ensureaccurate and permanent spacing. The construction of the form is such asto facilitate the practice of this method of spacing the D-coil windingsand simultaneously connecting and spacing the annuli 33.

Ribs or stays are also applied to the winding at this time if desiredand may under some circumstances be suflicient support for the coilswithout member 32. A convenient manner of applying these stays is toinsert strips 35 of celluloid into the grooves 20 during the windingoperation. If. these strips are now brushed with a small quantity ofacetone or banana oil they will soften and ad- 1 here to the adjacentportions of the windings. If further re-enforcement is neces sary, a tie36 may be used at the axis of the coil where the two diagonal portions27 and 29 of the windings cross each other.

When the windings thus far made have been adequately strengthened andsupported, the screws holding the form segments to the core arewithdrawn and the core is pulled axially from the two D-shaped coilsectors. The use of four or more segments ensures that there will be atleast two in each sector coil of the transformer and the spacing betweeneach such pair of segments permits their ready collapse for removal.This leaves a unitary assembly of skeleton support and winding suitablefor commercial use 1n that it will withstand a considerable degree ofhandling.

The remaining turns 24' of the secondary winding (which may compriseabout one quarter of the total number in winding 24) are wound in thesame way and inserted in the supplemental support 40, which takes theform of an annulus corresponding in diameter to annulus 33. -A sleeve 41guides the supplemental support for relative rotatlve movement on top ofthe main support. The two parts of the secondary winding are soconnected in series at 4:2 as to permit of such rotation to the extentof 180 if necessary. The primary winding and adjustable portion of thesecondary are preferably at the end of the transformer at which thesecondary is grounded or connected to the filament 1' return lead. Byrotation of the transformer unit assembled in the supplemental support40, the field of the secondary winding therein may be made to re-enforceor oppose the field of the secondary winding in the first unit so as tovary the algebraic sum of the inductances vof these two parts of thesecondar v i vhen a number of transformers made as above described areused for antenna or interstage coupling between a-udions or tubes in aradio signal receiver they may be tuned with a set of gang condensers45, 43 and 44.

change in the original distributed capacity.-

Thus each stage may be sharply tuned for high selectivity andperfectunity of resonance with other tuned circuits throughout the range ofadjustment of the tuning control.

Those skilled in the art will recognize in the form above disclosed asolution for the problems incident to the form winding of D-coils. Notonly can the coils be made to duplicate with great accuracy a desiredand predetermined structure, but it will be noted that the coils are ofan extremely low loss type with no material whatever within their fieldsand very little extraneous material near them. The spacing betweensuccessive turns of the windings is rendered permanent by stays 35,which ensures a permanently low distributed capacity.

It will be understood that this invention is not to be limited to thespecific constructions disclosed except insofar as limitations arecontained in the appended claims. I have not attempted to state the manyforms in which this invention may be practiced, and the disclosureherein. is to vbe understood as illustrative only. I have not attemptedto indicate the number of turns requiredin the different windings oftransformers made in accordance with this invention since the number ofturns will necessarily bevaried to suit various requirements. By way ofillustration, however, I will state that the broadcast wave band issatisfactorily covered by a transformer madecin accordance with thisinvention, wherein portion 24 of the secondary winding contains turnsthroughout both of the D-coils, and portion 24' of the secondary is madeup of 9 turns throughout both of the D-coils, the primary windingcomprising 8 turns throughout both D-coils. The diameter of a coilhaving the above number of turns may be approximately 2 inches, the wireused may be No. 24 D. C. C., and the condenser used for tuning may haveapproximately a capacity of .0005 mmf. With the above mentioned valuesas a. guide, other values can readily be determined by known formulas.

By way of further illustration of the fact that the above specificdisclosure is to be taken merely as representative of the manner inwhich this invention may be used, I wish to point out that instead ofplacing a portion of the secondary on the rotatable support 40 it'ispossible to place all of the secondar upon the skeleton support 32 andto place t e pri mary on the relatively-rotatable support 40. Therotative adjustment of the primary with reference to the secondary willhave the effect of varying the inductance of the transformersufiiciently to balance the several transformers of any given set, eachwith the other, in the manner above pointed out and I have further foundthat in such cases the balance will be less critical than the balanceobtained by adjusting a portion of the secondary. The less criticaladjustment is to be preferred for some purposes.

I claim:

1; The combination operatively in the tuning circuits of a radioreceiver, of an audion, a plurality of coupling transformers in theinput and outprt circuits of said audion having primaries andsecondaries, said secondaries being substantially identical inpredetermined capacity, means for adjusting the inductance value of thesecondary of one of said transformers without varying the predeterminedcapacity thereof, and means subject to single control for varyingsimultaneously the capacities of the secondaries of said transformers,whereby to tune each secondary simultaneously to resonance with a signalof a given frequency.

2. The combination with an audion tube having a grid and a plate,offirst and second transformers having portions connected respectivelyto said grid and said plate, a grid circuit including a secondary of oneof sald transformers, a plate circuit including a primary of the othertransformer, a secondary inductivelycoupled to the primary in said lastmentioned'transformer, both of said secondaries being of substantiallyidentical distributed capacity and one of said secondaries includingmeans for varying its inductive effect without altering its saidcapacity, and means for tuning said secondaries simultaneously to varythe frequency at which they are resonant, said means comprising likevariablecondensers shunted across said secondaries and provided withrotor blades subject to a common control.

3. The combination with an audion having a grid and a plate, oftransformers having portions connected respectively with said grid an'dsaid plate, each of saidtransformers including figure 8 primaries andsecondaries and having portions of their respective secondariesrotatably adjustable about the respective axes of the transformers,

whereby to vary the inductive effect of the secondary without materiallyaltering the distributed capacity thereof, together with like condensersof variable capacity shunted across each of said secondaries and eachin- '-whereby said inductances may be rendered uniform as to theirrespective values so as to have uniform increments of change 1nresonance during'the simultaneous control of said capacitances. j

5. In successive tuned circuits the combination with a plurality ofinductances having approximately identical distributed capacity, andeach having portions adjustable with reference to other portions thereofin a direction to vary their respective inductance values withoutmaterially varying such capacity, of

means for substantially synchronously varying the capacities of saidcircuits, said means including inter-connected variable condensersassociated with respedtive inductances, whereby said circuits will havesubstantially uniform increments of change in resonance under thecontrol of said condcnsers. v

6. The combination with an audion tube having a grid and a plate, of agrid coil connected with said grid, a transformer including a primaryand a secondary and having its primary connected with said plate,variable means for tuning said grid coil to res onance at a desiredfrequency, variable ineans for tuning said secondary to resonance at adesired frequency, the respective means having similar increments ofchange and being inter-connected for simultaneous operation, said gridcoil and secondary having substantially like values of distributedcapacity and each being provided with arelatively ad justable portionadapted to vary the inductance value of said coil without materiallyaffecting its capacity.

7. The combination of a plurality of tuned electrical circuits includingsimultaneously variable capacities and individually adjustableinductances fixed at like values.

8. The combination of a pluralit of tuned electrical'circuits includingsimultaneously variable capacities andindividually adjustableinductances, said capacities comprising inter-connected variablecondensers havin like increments of change of capacity, an saidinductances comprising coils shunting respective condensers, wound inthe form of a figure 8 and having like distributed capacities, each ofsaid coils having an individual adjustable portion rotatable withreference to another portion thereof, whereby to vary the interaction offields of said portions, and to modify the total inductance withoutmateriall altering the distributed capacity.

9. he combination in aplurality'of tuned circuits, of synchronouslyvariable resonance, said circuits including figure 8 D-coils havingsuccessive portions of their respective windings-intersecting atrelatively acute angles at the common axis of said coils, said coilsbeing of similar distributed capacity, similar variable condensers inthe respective circuits connected together for simultaneous variableoperation whereby simultaneously to vary the capacity and points ofresonance of the cal respective circuits and means for supporting aportion of the winding of one of said figure 8 D-coils for rotativeadjustment about said axis, whereby to vary the total inductance of saidcoil without material variation of its distributive capacity.

10. In combination, a plurality of tuned circuits, each comprising aninductance and a variable capaclty, of single control means providedwith means for synchronously varying the capacities of the severalcircuits, and inductance varying means for co-acting individually withthe inductance of each circuit for separately adjustingand fixing saidcircuit in resonance.

MARC A GlBLlN.

